How Much Carbon Is on Earth?

There are approximately 1.85 billion, billion tonnes of carbon present on planet Earth – and only a tiny fraction of that is found in the air we breathe. The vast majority (more than 99%) of it is actually stored within the Earth’s crust, according to a startling new study conducted by a team of scientists from the Deep Carbon Observatory (DCO) project.

The ground-breaking research took ten years to complete and represents the first investigation of its kind. The work not only puts into perspective the relatively tiny amount of carbon present in the atmosphere, but also helps to contextualise how the Industrial Revolution and manmade climate change have disrupted the normal ebb and flow of carbon from within the Earth itself.

Under our feet

The majority of concerns around climate change focus on the carbon that is present in the air all around us, and governments across the world have been putting in place measures (like the medium combustion plant directive) in an attempt to control it. However, it might come as quite a shock to know that the 43,500 billion tonnes of carbon present in our atmosphere represents just 0.2% of the total carbon on Earth.

Instead, the vast majority of this most abundant of resources is found beneath our feet. “Very little was known about its form, how much there was, and how mobile it is,” explained one of the collaborators on the DCO study. “And, obviously, this all has huge importance for both the climate of the Earth, but also the habitability of our surface environment.”

A painstaking project

In order to quantify the amount of carbon on Earth, the DCO spent a decade using sophisticated methods of measuring atmospheric emissions from volcanoes all across the Earth, as well assessing samples of deep-sea sludge which is drawn into the Earth’s crust at the boundaries of tectonic plates. They then used laboratory experiments and computer models to create a simulation of probable carbon flows and stores underground.

They were also able to develop a simulation of how they believe the carbon budget of the Earth’s crust may have changed over time, creating a picture of its evolution through millennia. The results showed that the overall amount of carbon has stayed relatively constant throughout the last billion years, with similar amounts being expelled as those which were drawn through tectonic fissures.

On the brink?

However, the team did note that there were certain exceptions to this rule, when the normal status quo was upset considerably. This was most often caused by a large-scale impact from a meteor strike or by prolonged periods of volcano eruptions. The result of these episodes was a very high concentration of carbon in the atmosphere, leading to elevated temperatures above ground, acidic ocean waters and even mass extinctions of species living on the planet at the time.

The concern is that the current spike in carbon emissions caused by anthropogenic activity might represent a similar anomaly. Given that fossil fuel combustion has contributed to carbon emissions that are between 40 and 100 times greater over the last century than the average for the last billion years, it’s plausible that we may currently be on the brink of another mass extinction.Controlling the release of carbon in an industrial setting, therefore, is of paramount concern. The e-learning session Transforming Wastewater Treatment with TOC Monitoring is a key resource in understanding how plants, factories and other facilities can gain a better understand of their carbon footprint at the effluent stage.